The invention relates to a magnetically controlled switch with contacts wetted by a conductive liquid.
Switches with contacts wetted by a conductive liquid, generally in the form of mercury or a mercury amalgam are known in the art and are normally called mercury wetted switches. This category of electrical switches is generally constituted by a system of associated plates, whereof at least one has a certain flexibility. They are sealed into a glass envelope into which has been introduced an adequate quantity of mercury to wet the plates. The main advantage of this type of switch is that it offer a very good electrical contact, without impairing the contacting surfaces because they are wetted by mercury. However, it frequently has the disadvantage of using methods for sealing the plates in the glass envelope which are complicated and onerous, while leading to the contamination of the electrical contacts during the sealing within the glass. Moreover, it is necessary to machine the flexible plates and the dimensions required by the plates make the overall size of the switch relatively large. Finally the fact that the plates are sealed within an envelope calls for a setting or adjustment, particularly of the sensitivity. When in use the mercury vaporizes during breaks on the contacts and is partly deposited within the glass envelope, so that the amount of mercury on the contacts is reduced, so that a mercury reserve must be maintained within the envelope. As a result of this mercury reserve the operation of the switch in the envelope must be ensured in a clearly defined position in such a way that the mercury reserve present does not short-circuit the contacts.
Thus, an adaptation of the existing techniques of mercury wetted switches requires:
a design permitting the use of the switch in such a way that it is position-independent, particularly with respect to the vertical of the location; PA1 a simplification of manufacturing conditions involving more particularly the elimination of contact contamination during the sealing operation, the elimination of flexible plates which need to be machined and the elimination of the actual sealing operation which is always difficult on ever-smaller devices; PA1 a reduction in the switch dimensions in such a way that it is possible to miniaturize the relay and automatically fit its components by means of an automatic machine. PA1 a metal plate in which the flexibility is of no significance because it is movable, without requiring the use of mechanical hinges as has been done in certain known switches; PA1 a liquid hinge constituted by mercury or any other conductive liquid which also ensures electrical contact between the moving plate and the pivot axis constituted by two pins between which is slid one end of the plate; PA1 two electrical contacts, generally called the make and break contacts, formed by two pins against which abut the end of the plate opposite to that located in the liquid hinge.